Apparatus and method for angle-dependent processing

Abstract: A method and apparatus determines an angular location on a round object (3) during a current operation in order to facilitate the positioning of that object for subsequent operation. At a first station (1), an angular location identifying feature (A) is sensed, and an angle (C) at which a pre-determined desired angular location (B) is located with respect to the feature (A) is determined. At a second station (1), the feature (A) is sensed, the object (3) is indexed from the feature in an amount equal to the angle (C) to re-locate the desired angular location (B), and the object (3) is processed at the re-located pre-determined desired angular location (B). This processing step may be a marking step at the second station, but may be the performance of the subsequent operation. The first station means includes means for sensing the angular location identifying feature on the object (3) and measurement means for determining the angle (C) at which a pre-determined desired angular location (B) on the object is located with respect to the feature (A). The second station means includes sensing means for sensing the feature (A), indexing means for indexing from the feature in an amount equal to the angle (C).

Description: The invention relates to angle-dependent processing of objects such as tyres, wheels or tyre/wheel assemblies wherein the processing of the object at a given processing station requires angle-specifying information generated or defined previously at some other processing station. In the processing of round objects, it frequently becomes necessary to perform a subsequent operation based on an angular location on the object identified in a current operation. Normally, this requirement is achieved by placing a mark upon the object during the current operation. That mark is then used as a reference for positioning of the round object during the subsequent operation. In the processing of automobile tyres and wheels, see for example WO-A-92/01918, it is known to place a mark upon the tyre at an angular location corresponding to the high point of the first harmonic of the radial force variation of the tyre, and to form a valve stem hole on the wheel at an angular location corresponding to the low point of the first harmonic of the average radial run out of the wheel. During subsequent processing, when the tyre is mounted upon the wheel, it is desirable to align the tyre and wheel such that the marks are at the same angular location. This effectively reduces radial force variation in the resulting tyre/wheel assembly. However, physically placing marks upon the objects consumes cycle time and thus reduces process throughput. For example, in order to form a visible mark on the side wall of a tyre at a location identified by a tyre uniformity machine, it is necessary to substantially stop rotation of the tyre with the high point of the radial force variation oriented in the direction of the marking devices, and to then wait while the mark is applied to the tyre. These steps can consume as much as 5% of the machine's cycle time on the average. In other equipment, it has been known to reduce this consumption of cycle time by providing a second station on the machinery dedicated to carrying out the marking operation. While this second station adds expense to the machinery, it is nonetheless frequently beneficial to the cost effectiveness of the machinery to perform the marking operation at this second station. However, in tyre uniformity machinery, it is not possible to accurately apply an angular mark at a second station of the machine. This is so because the tyre must be "stripped" from the test rim of the first station and them moved to the second station; this causes loss of angular orientation of the tyre. It is therefore desirable to provide a method of and apparatus for overcoming the difficulties associated with the current practices, and to provide a faster throughput in processing round objects such as tyres and wheels. According to a first aspect of this invention a method of processing round objects, including determining an angular location on a round object during a current operation in order to facilitate positioning the object for a subsequent operation, comprises: (1) at first station, a) sensing an angular location identifying feature on the object, and b) determining an angle at which a pre-determined desired angular location on the object is located with respect to said feature; (2) at a second station, a) sensing said feature, b) indexing from said feature in an amount equal to said angle thereby re-locating said pre-determined desired angular location with respect to said feature, and c) performing the subsequent operation on the object, the subsequent operation being dependent on said re-located pre-determined desired angular location. The object may be an automobile wheel wherein the identifying feature is a valve stem hole, or an automobile tyre wherein the identifying feature is an auxiliary mark applied thereto at a random location. Such an auxiliary mark could be in the form of, for example, a label. The identifying feature could as well be determined by auto-correlation. In order to automate the method, the angle can be stored at the first station and then recalled at the second station. Indexing can then be performed as described. The angle can be stored in computer memory or in any number of tangible media, which media may be human-readable or machine-readable, such as printed bar code, magnetic floppy disks, or magnetic tape. The tangible media can be affixed to the object so that the angle can be recalled should the object be transported to a remote location for the marking step. The subsequent operation may include a marking step carried out at the second station but, alternatively the subsequent operation may itself be carried out at the second station and be, for example the pairing of tyres with wheels. According to a second aspect of this invention an apparatus for determining an angular location on a round object during a current operation in order to facilitate positioning said object for a subsequent operation, comprises: first station means, said first station means including sensing means for sensing an angular location identifying feature on said object, and measurement means for determining an angle at which a pre-determined desired angular location on said object is located with respect to said feature; and second station means, said second station means comprising sensing means for sensing said feature, and indexing means for indexing from said feature in an amount equal to said angle thereby re-locating said pre-determined desired angular location with respect to said feature. Data storage means can be employed to store the angle at the first station means, to be recalled subsequently at the second station means for the indexing step. The second station means can further include marking means for marking the object with a mark at the re-located pre-determined desired angular location. One advantage of the present invention is that throughput loss caused by marking angular locations on round objects has been reduced. Another advantage of the present invention is that, if desired, the entire step of marking an angular location on a round object for performing a subsequent operation thereon may be eliminated. A particular example of a method and apparatus in accordance with the present invention will now be described with reference to the accompanying drawings, in which:- Fig. 1 is a flow chart illustrating a method of determining an angular location on a round object during a current operation in order to facilitate positioning the object for a subsequent operation; Fig. 2 is a flow chart illustrating a method of processing round objects which includes determining an angular location on a round object during a current operation in order to facilitate positioning the object for a subsequent operation; and Fig. 3 is a schematic of apparatus capable of carrying out the methods of the present invention. With reference first to Figs. 1 and 3, there is illustrated a flow chart F1 for determining an angular location on a round object during a current operation in order to facilitate positioning the object for a subsequent operation, and apparatus 10 therefor, respectively. Referring specifically to Fig. 3, there is illustrated a round object 3, and first and second stations 1 and 2 for processing the round object 3. The round object 3, in the preferred practice of the present invention, is either an automobile tyre or an automobile wheel. Upon round object 3, A designates an angular location identifying feature. This feature A could take various forms, one of which could be a valve stem hole in a tyre wheel, or an arbitrarily placed label on the side wall of a tyre. A pre-determined desired angular location B is known, and it is desired to determine the angle C at which this pre-determined desired angular location B resides with respect to the angular location identifying feature A for marking of the object 3 at location B to facilitate subsequent processing of the round object. Specifically, B represents the high point of the first harmonic of the radial force variation of the tyre, or alternatively the low point of the first harmonic of the average radial run out of the wheel. It can be assumed, for the practice of the present invention, that the high point of the first harmonic of the radial force variation of the tyre has been previously determined with a conventional tyre uniformity optimizer, and is readily identifiable by first station 1. Similarly, the low point of the first harmonic of the average radial run out of the wheel has been previously determined by a conventional wheel uniformity analyzer, and likewise is readily identifiable by first station 1. Therefore, it will be appreciated that as round object 3 enters first station 1, the first station 1 is able to determine the position B on the round object 3 based on the previous results of the wheel uniformity analyzer or tyre uniformity optimizer, as is the case. After round object 3 has entered the first station 1, sensing means within the first station 1 senses the angular location identifying feature A on the object 3, as instructed by step S11 of flow chart F1. As previously mentioned, the identifying feature A would normally take the form of a valve stem hole for an automobile wheel, and an auxiliary mark, such as a label, applied at a random angular location on an automobile tyre. The sensing means of the first station 1 for sensing the identifying feature B could be any number of conventional sensing means, and could employ a physical contact probe, such as would pick up a valve stem hole in an automobile wheel, or could just as easily be a non-contact probe such as an optical sensor. Furthermore, utilizing a non-contact probe such as optical sensor, the signal processing technique of auto-correlation could be employed to determine an identifying feature. Once the first station 1 has identified the angular location identifying feature A on the object 3, the station 1 then determines, by any conventional measuring means, the angle C at which the pre-determined desired angular location B is located with respect to the feature A, as instructed by step S12 of flow chart F1. In order to mark the round object 3 at the desired location B, it is necessary to store or otherwise record the angle C for subsequent recollection at the second station 2, wherein the marking will occur. Accordingly, the angle C can be stored, for example, in computer 4 by the first station 1, for subsequent recall by the second station 2. This scenario would be ideal in the warehouse-type manufacturing and assembly operation wherein the angle C is determined at one location in the warehouse, and the object 3 is then transported to another location within the same warehouse or manufacturing facility for the subsequent marking operation to be performed on the object 3. Alternatively, the round object 3, be it an automobile tyre or an automobile wheel, may be transferred to a remote assembly plant for marking. In this scenario, the angle C can readily be stored in any number of tangible media. Such media could be human-readable, or in a preferred embodiment, would be machine readable, such as printed bar code, a magnetic floppy disk, or a magnetic tape. In this scenario the tangible media would be affixed to the object 3 and transported therewith to the remote location so that the angle C could be recalled utilizing conventional data recollection means and the subsequent marking be performed on the object 3 thereat. Accordingly, step S13 of the flow chart F1 involves sensing the identifying feature A at the second station 2, by such means as previously described. Step S14 at the second station 2 involves indexing from the identifying feature A in an amount equal to the angle C thereby relocating the pre-determined desired angular location B with respect to the identifying feature A. Of course, any conventional rotary indexing means can be employed to perform this step S14. Finally, step S15 involves marking the object with a mark D at the re-located desired angular location 8. At this point, the round object 3, be it an automobile tyre or wheel, is ready for pairing to an automobile wheel or tyre, respectively, as the case may be, and may be done so by simply matching the marks D prior to assembly. Another method of the present invention is illustrated in Fig. 2 as flow chart F2. In flow chart F2 the marking step S15 of flow chart F1 is eliminated, and the subsequent operation to be performed on the object, namely, pairing, which is dependent on the pre-determined desired angular location, is performed at the second station 2 as step S25. The method of flow chart F2 would be ideal for a warehouse-type manufacturing and assembly operation wherein the angle C is determined at the first station S1, and the object 3 is then transported to another location within the same warehouse or manufacturing facility for subsequent processing to be performed on the object 3, as for example pairing of tyres with wheels. Similarly, the round object 3, be it an automobile tyre or an automobile wheel, may be transferred to a remote assembly plant, or to an automobile manufacturer, for subsequent pairing and assembly of tyres with wheels. As previously described, if the second station is located in the same warehouse or factory facility as the first station, the angle C can be stored in a computer 4 by the first station 1 for subsequent recall by the second station 2. Further, any conventional data transmission means, such as local area networks, may be employed therefor. And, as described earlier, should the automobile tyre or automobile wheel be transferred to a remote assembly plant or to an automobile manufacturer, the angle C can be readily stored in any number of tangible media, which can be affixed to the object 3 and transmitted therewith such as printed bar code, a magnetic floppy disk, or a magnetic tape.

Claims: A method of processing round objects (3), including determining an angular location on a round object (3) during a current operation in order to facilitate positioning the object for a subsequent operation, the method comprising: (1) at first station (1), a) sensing an angular location identifying feature (A) on the object (3), and b) determining an angle (C) at which a predetermined desired angular location (B) on the object (3) is located with respect to said feature (A); (2) at a second station, a) sensing said feature (A), b) indexing from said feature (A) in an amount equal to said angle (C) thereby re-locating said pre-determined desired angular location (B) with respect to said feature (A), and c) performing the subsequent operation on the object (3), the subsequent operation being dependent on said relocated pre-determined desired angular location. A method according to claim 1, wherein the object (3) is an automobile wheel and the identifying feature is a valve stem hole or wherein the object is an automobile tyre and the identifying feature is an auxiliary mark such as a label applied to it at a random angular location. A method according to claim 1 or 2, wherein said identifying feature is determined by auto-correlation. A method according to any one of the preceding claims, wherein said angle (C) is stored at the first station and is recalled at the second station. A method according to any one of the preceding claims, in which the subsequent operation includes marking the object (3) at the pre-determined desired angular location (B) with a human or machine readable mark. A method according to any one of claims 1 to 4, wherein the method is performed on an automobile wheel or tyre and the subsequent operation is the association at a particular mutual angular orientation of said automobile wheel or tyre with a corresponding tyre or automobile wheel. An apparatus (10) for determining an angular location on a round object (3) during a current operation in order to facilitate positioning said object (3) for a subsequent operation, said apparatus comprising: first station means (1), said first station means including sensing means for sensing an angular location identifying feature (A) on said object (3), and measurement means for determining an angle (C) at which a predetermined desired angular location (B) on said object is located with respect to said feature (A); and second station means (1), said second station means comprising sensing means for sensing said feature (A), and indexing means for indexing from said feature in an amount equal to said angle (C) thereby re-locating said predetermined desired angular location (B) with respect to said feature (A). An apparatus according to claim 7, wherein said first station means (1) further includes storage means for storing said angle (C) and said second station means (1) further includes recall means for recalling said angle (C). An apparatus according to claim 7 or 8, wherein second station means further includes marking means for marking said object (3) with a mark.

Inventors: BEEBE JAMES C, BEEBE, JAMES C.
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1994
Main classification: G01M1
IPC codes: B60C25, G01M1